This invention relates to a caster and more particularly it relates to a caster whose inherent function of automatically changing the direction of the wheel can be selectively stopped.
Casters of this type are advantageous particularly when attached to a baby carriage, for example. That is, if such casters are attached to the lower ends of leg members, e.g., front legs, of a baby carriage, the baby carriage can be smoothly moved even if the pushing force thereon is weak. Further, it can be easily changed in the direction of travel even in narrow aisles as in stores. On the other hand, on a gravel road, for example, if the casters are in the state of being capable of changing the direction of the wheels on the basis of their inherent function, the casters allow the wheels to fluctuate more than is necessary; thus, the inherent function of the casters does more harm than good, making it rather hard to push the baby carriage. Thus, an improved caster is constructed so that its inherent function can be stopped, as needed.
Such improved caster is advantageous in that it ensures satisfactory steerability at all times depending upon the condition of the road.
A point to be desired in the aforesaid type of caster is as follows.
For example, when the baby carriage is being moved with the inherent caster function stopped and with the direction of the wheels fixed, if the wheels come across a relatively large difference in level, sometimes a great shock is transmitted from the wheel to the operative portions of the caster. In such case, the caster could be fatally damaged. In this case, if the wheel is allowed to change the direction, the aforesaid situation of the wheel coming across a difference in level results in the wheel changing the direction, whereby the shock can be successfully absorbed, being prevented from leading to damage to the caster. Thus, it is desired that when such shock is applied to the wheel, the state in which the inherent function of the caster is stopped is immediately cancelled.